Composite Textile Material for the Manufacturing of Thermoformed Products, Method and Machinery for its Manufacturing

ABSTRACT

The invention refers to a composite material developed for manufacturing thermoformed products with applications in furniture making, automotive industry, etc., a method and machinery for the manufacturing of the material in unwoven form. The composite material for thermoforming is made of a thermoplastic fibrous component consisting of 4-60 mm long and 7-16 DEN fine polypropylene fibers representing 40% to 50% of the total material weight and a plant fiber component which can be hemp, jute, sisal, coconut, etc., or a mix of natural fibers which is 70-80 DEN fine and 5 to 100 mm in length and represents 60% to 50% of the total material weight. The process for manufacturing the claimed composite material consists in taking and proportioning the components, followed by their mixing and coarse defibering and then a fine mixing in a four-chamber module which also opens the natural fibers to 70 . . . 80 DEN fine, followed by the consolidation of the fibers and, finally, the rolling of the resulting fabric in a roll. The machinery for the manufacturing of the claimed composite material has a modular structure, comprising two modules ( 1  and  2 ) for feeding the components, two modules ( 3  and  4 ) for weighing and proportioning the components, a primary mixing and coarse defibering module ( 5 ), a module ( 7 ) for the fine mixing and fibre opening, an interlacing module ( 8 ) and a module ( 9 ) for pulling and rolling the final fabric.

The invention refers to a composite material developed for manufacturing thermoformed products with applications in furniture making, automotive industry, etc., a method and machinery for manufacturing the material in unwoven form.

The majority of upholstered products have a structure in the form of a wood frame. The wood is an excellent material from a functional, ecological and esthetic viewpoint, but the excessive cutting of trees is starting to take its toll on the environment, and so most of the countries now have very strict logging laws. Due to this reason the manufacturers of large series products that contain wood, among which the furniture manufacturers can be found, are looking for solutions to replace wood with other recyclable materials that offer advantages regarding the productivity and the general cost of the product. For this purpose a series of composite materials made of natural and thermoplastic fibers have been developed, materials which can be thermoformed so as to replace products made of wood.

Patent RO 115182 “Nonwoven textile material and process for its manufacturing” shows a nonwoven layered material that is used mainly in the manufacturing of drainage systems. The material is formed of at least three layers which have alternating fiber thicknesses. The odd layers are formed of 4 . . . 10 DEN and 60 . . . 100 mm long polyester fibers, and the even layers are made of monofilament 160 . . . 220 DEN and 80 . . . 100 long polyester fibers. The manufacturing process of the non-woven textile material is done by carding-interlacing of the odd layers, while the even layers are made by forming a fibrous fabric using compressed air. The final assembly is done by interlacing with needles of size 15×18×32×31/2″, with an interlacing density of 150 needle stickings/cm² and a depth of travel of 9 mm.

The described composite material does not have thermoforming specific properties and the manufacturing method of carding-interlacing is not efficient for making a composite fabric used in thermoforming.

Patent WO2006052967 “Composite thermoplastic sheets including natural fibers” shows a laminated composite material that is made of a porous core that includes at least one thermoplastic material and natural fibers of jute, linen, hemp, coconut, etc., which make up 80% of the total weight of the porous core. This material is used in numerous products because of its ease of manufacturing through thermoforming. Among the products made so one can find decorative panels for car interiors or public transportation systems and architectural use. The manufacturing method of the composite involves mixing natural fibers with a length of 5 to 50 mm with a thermoplastic resin powder in order to obtain an aqueous foam mix. The natural fibers are set on a wire mesh, then the water is drained and the fibers are heated and compressed to obtain a porous sheet of the desired thickness.

The disadvantage of this method of manufacturing the composite material lies in the difficulty of draining the aqueous solution completely before rolling the material onto rolls. Burning these materials to dispose of them at the end of lifecycle is an impractical solution because they contain fiberglass.

Patent KR970008215 “Thermoplastic composite material reinforced with hemp fibers” refers to a composite material made of a thermoplastic reinforced with hemp fibers and filler represented by wood. The wood filler can be particles, powder or chips and is dispersed homogenously throughout the thermoplastic matrix. The thermoplastic can be polypropylene, polyethylene, a copolymer of ethylene and polypropylene, a copolymer of acrylonitrile-butadiene-styrene or simply nylon. The thermoplastic material may contain anorganic filler such as talcum or plastifiers/lubricants depending on the desired properties. The composite is manufactured as sheets used in die-cutting or pellets used in injection molding.

Patent FR2781492 “Composite thermoplastic material for use in production of various molded articles, includes hemp fibers of specified dimensions and humidity” refers to a thermoplastic composite which includes hemp fibers of sizes and humidity fit for molded products. The composite material is formed of a thermoplastic with a maximum melting point of 200° C. and hemp fibers shorter than 2 mm and with a diameter smaller than or equal to 0.2 mm. The hemp fibers' humidity is maximum 4% of the fibers' mass. The patent describes a method of manufacturing the material that consists of melting the thermoplastic and mixing hemp fibers into it.

The disadvantage of the material obtained by the patented method consists of the fact that it has small strength due to the short fibers and is recommended to be used in injection molding and less for thermoforming.

Patent DE19950744 “Production of a thermoplastic composite material involves mixing and compressing starch-based polymers with shavings of natural plant fibers, followed by melting, homogenization and granulation” refers to the fabrication of a composite thermoplastic material through the mixing and compressing of starch-based polymers with natural fibers, followed by melting, homogenization and granulation of the obtained material. The novelty consists of using a plant derived polymer which together with the natural fibers produces a biodegradable material. The composite material is fabricated by heating the thermoplastic to 120° C. between the laminating rollers, followed by the mixing of natural fibers and homogenization between another set of rollers and the granulation of the material through cooling at the end.

The disadvantages of the known materials consist either in the weak mechanical properties or in the specific weight and specific strength.

The problem solved by the present invention is the manufacturing of a composite material suited for making thermoformed articles, the material being low-cost, 100% recyclable, needing a low content of synthetic materials derived from hydrocarbons and having the advantage of being made primarily out of a fast growing natural resource.

The composite material for thermoforming is made of a thermoplastic fibrous component consisting of 4-60 mm long and 7-16 DEN fine polypropylene fibers representing 40% to 50% of the total material weight and a plant fiber component which can be hemp, jute, sisal, coconut, etc., or a mix of natural fibers which is 70-80 DEN fine and 5 to 100 mm in length and represents 60% to 50% of the total material weight.

The manufacturing process of the composite material consists of the following operations:

a. taking the plant fibers from the bale and cutting them to lengths between 5 and 100 mm, using a rotating blade chopping machine

b. simultaneous weighing of the plant fibers resulted from the previous phase and polypropylene fibers with a length of 60 mm and 7-16 DEN fine using two scales, opening the chutes and periodically releasing a quantity between 0.5 and 2 kg on a conveyor belt in order to obtain a mix for the composite material of which the plant fibers represent 50-60% of the total mass

c. coarse mixing of the plant and polypropylene fibers and defibering them with the help of a fiber opener with nails, then transferring the material to a mixer with four vertical chambers

d. mixing and finely shredding the materials which is carried out at first in the chambers of the four chamber mixer where the material is fed by compressed air in order to obtain the mixing of the two components, then comes the second phase, where the fibrous material from each of the chambers is shred with the help of the nail rollers which feed fibrous layers onto a conveyor belt where four overlaid layers are made, one from each chamber of the mixer, this allowing an optimum homogenization of the two components, then the obtained material is sent to another feeder which transfers the material with the help of compressed air to the surface of two perforated rollers which rotate in opposite directions and create a blanket that is homogenous in terms of weight/surface unit

e. interlacing the material with the help of barbed needle machines which consolidate the fibrous layer by routing the upper layer fibers to the lower layer and the fibers in the lower layer to the upper layer, increasing the strength of the fibrous material and implicitly reducing its thickness by a factor of 4 to 5

f. pulling and rolling the material with the help of two rollers in order to make a fabric with consolidated fibers (by interlacing) and packaged as a roll

The machinery for producing the composite material consists of at least two feeding modules, one for the thermoplastic fibers and the other for the plant fibers, one module which weighs and feeds correct proportions of each type of fiber, one module for the primary mixing and the coarse defibering, one module for the fine mixing and defibering, one module for interlacing and one module for pulling and rolling the material.

The following presents an example of such a machinery with the help of FIGS. 1 and 2 which represent:

FIG. 1 represents the modular structure of the machinery for the manufacturing of the composite material

FIG. 2 represents the technological schematic of the machinery for the manufacturing of the composite material.

The machinery for the manufacturing of the composite textile material is made of the following modules:

-   -   module 1, which takes the plant fibers from the bale, chops them         to the predetermined length and feeds them to the next module;     -   module 2, which feeds the thermoplastic fibers to the next         module;     -   module 3, for weighing and periodical feeding of the plant         fibers on a conveyor belt 5 a of module 5, for primary         homogenization;     -   module 4, for weighing and periodical feeding of the         thermoplastic fibers on a conveyor belt 5 a of module 5;     -   module 5, for the homogenization and primary opening of the         textile fibers;     -   module 6, for the homogenization and fine defibering to a value         of 70-80 DEN;     -   module 7 for the compressing and forming of the composite         fabric;     -   module 8, for the interlacing;     -   module 9, for the rolling of the obtained fabric.

Module 1 consists of a conveyor belt 1 a that has a roller 1 b at one end, which feeds the plant fibers FV to a chopper 1 c, with rotating blades 1 d. Chopper 1 c cuts the plant fibers FB to a length between 5 and 100 mm. The length of the fibers is set by tuning the speed of the conveyor belt 1 a with the speed of the rotating blades 1 d. The shortened plant fibers FV go through a pressing device 1 e and are then transferred on a horizontal conveyor belt 1 f, then onto an inclined conveyor belt 1 g. Conveyor belt 1 g has nails which prevent the material from sliding on it. This way conveyor belt 1 g takes a great part of the fiber quantity and the formed fibrous layer will be equalized by the equalizing roller 1 h that rotates opposite to the travel direction of the inclined conveyor belt, and the excess material will fall onto conveyor belt 1 g which will homogenize the fibrous material.

Plant fibers FV are transferred in the direction of arrows A1 and B1 of module 3 at a constant flow.

Module 2, for the feeding of the thermoplastic fibers FT is composed of a conveyor belt 2 a and a conveyor belt 2 b, that is inclined and has nails. The thermoplastic fibers FT are transferred in the direction of arrows A2 and B2 towards module 4 at a constant flow that is tuned by the equalizing roller 2 c.

Module 3 consists of a decompressing roller 3 a, which takes plant fibers FV from conveyor belt 1 g, and a weigh hopper 3 b. Weigh hopper 3 b weighs and releases equal quantities of plant fiber FV onto conveyor belt 5 a.

Weigh hoppers 3 b and 4 b open periodically and empty onto conveyor belt 5 a the necessary quantity of each component of the composite in order to obtain the right mix percentages.

Module 5, used for the homogenization and primary opening of the textile fibers, takes quantities of each material component from conveyor belt 5 a periodically and, with the help of roller 5 b which is a nail decompressor, the material is transferred into compressor 5 c. The material passes between two feeding rollers 5 d to fiber opener 5 e, and then together with two other feeding rollers 5 f goes to a horizontal fiber opener 5 g. The horizontal opener ensures that the fibers get opened up to 150-200 DEN fine.

A pressure switch 5 h controls the feeding of condenser 5 c depending on the value of the pressure inside it.

The mix is sent from the horizontal opener 5 g through tubing 5 i to module 6 for homogenization and fine defibering.

Module 6 is fed with a mix of fibers through the upper part of the four vertical chambers 6 a, 6 b, 6 c and 6 d. Each vertical chamber 6 a, 6 b, 6 c and 6 d is fitted with two feeder rollers 6 e and fiber opener roller 6 f.

For a better homogenization of the textile fibers with the thermoplastic fibers, conveyor belt 6 g periodically releases approximately equal quantities of mixed material from each of the chambers 6 a, 6 b, 6 c, 6 d by controlling the timing of the feeder rollers 6 e of the chambers using photocells 6 h.

From conveyor belt 6 g the fibrous material mix goes to fiber opener 6 i which opens the material to 70-80 DEN, and from here, through tubing 6 j, the material goes to compression module 7.

Compression module 7 contains compressor 7 a. The fibrous material is detached from condenser 7 a and falls into the aspiration bunker that controls the flow using photocell 7 b, and is then taken by the feeding rollers 7 c and opened by the fiber opener roller 7 d.

A rigid gasket with saw like teeth sends fiber packages to the surfaces of the two perforated rollers 7 e which rotate opposite to one another (arrows 7 g) thus obtaining a uniform thickness of the fabric which is then detached by a deflecting shield. Thus, the fabric is lead onto conveyor belt 7 h and from here on to module 8, for the interlacing.

Module 8 contains 3 interlacing machines 8 a, 8 b and 8 c. Each machine has a set of barbed needles that pass the fibers from the upper layer to the lower layer and vice-versa, thus obtaining a consolidation of the fibrous material through the interlacing of the fibers.

Next the consolidated material is taken up by a rolling module 9 with the help of rollers 9 a and lead to the rolling system that consists of two lower rollers 9 b which rotate in the same direction and package the composite material in the form of roll 9 c.

The main differences in the proposed technological process as compared to the known solutions are presented in table 1.

TABLE 1 Operation Existing solution Proposed solution Component fiber opening uses a double card which subjects uses a nail fiber opener with the fibers to stress and results a rigid gasket that protects the in fibers of different lengths fibers' characteristics fibers with a high wood content a large array of fibers can cannot be opened be used, including plants with more than 20% plant fiber content Machinery cost more expensive and higher maintenance shorter workflow machinery easier maintenance limited carding capability 2-3 times higher capacity high energy consumption 60% of the energy consumption of the existing processes Component mixing double card four chamber mixing around 30-40% waste results from module the opening and mixing stage waste is under 10% Fibrous layer making the forming is done by plying the the forming of the fibrous layer fibrous layer that exits the card makes fibers with multiple orientations limited capacity due to the chopping 2 to 3 times greater processing capacity speed of the plyer The textile material can be used for various applications:

-   -   automotive industry: dashboards, front bumpers, door interiors,         consoles, trunks, etc.     -   furniture industry: sofas, tables, furniture, hangers, mirror         frames, chairs, drawers     -   products for home use: trays, dishes, etc.         By applying the invention the following advantages are obtained:     -   obtaining recyclable materials, that do not contain toxic         compounds, with multiple applications (automotive industry,         furniture industry, home goods, etc.)     -   rapid growth raw materials are used which can grow anywhere on         earth     -   reduced dependency on hydrocarbons     -   reduced water consumption in both the production of the raw         material as well as in manufacturing     -   reduced electric energy consumption/kg of material     -   low workforce needed and fast productivity growth     -   the manufacturing process uses machinery specific to plant         fibers which is easy to build and run     -   the technology doesn't pollute because the waste can be reused         in the manufacturing of new material and doesn't give off toxic         gases into the atmosphere. 

1. A composite textile material for the manufacturing of thermoformed products composed of a thermoplastic fibrous component represented by polypropylene fibers and a plant fiber component which can be composed of hemp, jute, sisal, coconut or other fibers, characterized by the fact that it's formed of polypropylene fibers with a length of 4-60 mm and 7-16 DEN fine at a percentage between 40% and 50% of the total weight of the composite material, and of plant fibers derived from hemp, jute, sisal, coconut, etc., which are opened to 70-80 DEN fine and a fiber length of 5 to 100 mm at a percentage between 60% and 50% of the total composite material weight.
 2. The manufacturing process for the composite textile material, consisting of proportioning, mixing, consolidation and rolling phases is characterised by the fact that it consists of the following operations: a. taking the plant fibers from the bale and cutting them to lengths between 5 and 100 mm, using a rotating blade chopping machine b. simultaneous weighing of the plant fibers resulted from the previous phase in one weighing hopper and polypropylene fibers with a length of 60 mm and 7-16 DEN fine in another weighing hopper, opening the chutes and periodically releasing a quantity between 0.5 and 2 kg on a conveyor belt in order to obtain a mix for the composite material of which the plant fibers represent 50-60% of the total mass c. coarse mixing of the plant and polypropylene fibers and defibering them with the help of a fiber opener with nails, then transferring the material using compressed air to a mixer with four vertical chambers d. mixing the components and finely opening their fibers with the help of four nail rollers, each roller taking out and laying one fiber layer at a time from each chamber on a conveyor belt, thus creating four overlaid layers and ensuring an optimum homogenization of the two components, then sending the material to a feeder hopper which transfers the material with the help of compressed air to the surfaces of two perforated roller which spin in opposite directions to one another and create a fabric that is homogenous in terms of the mixing of the components and of weight/surface unit e. consolidation of the so obtained fabric by interlacing the material with the help of a machine with barbed needle, which increase the strength of the fibrous material and implicitly reduce its thickness by a factor of 4 to 5 f. pulling and rolling the material with the help of two rollers in order to make a fabric with consolidated fibers and packaged as a roll.
 3. The machinery for manufacturing the composite textile material consists of feeder modules (1) and (2) for plant fibers (FV) and for thermoplastic fibers (FT), a module for the proportioning that weighs and proportions the components, a module for pulling and rolling the composite fabric (9), characterized by the fact that it is designed as a modular structure which consists of at least one module (1) which feeds the plant fibers (FV), a module (2), which feeds thermoplastic fibers, at least one module (3) for the weighing and periodical release of the plant fibers (FV) and a module (4), for the weighing and periodical release of the thermoplastic fibers (FT) onto a conveyor belt (5 a) of a module (5), for the homogenization and primary opening of the textile fibers with a horizontal fiber opener (5 g) to 150-200 DEN fine, a module (6) for the homogenization and fine opening, composed of four chambers (6 a, 6 b, 6 c, 6 d) out of which come four overlaid layers of fibrous material onto a conveyor belt (6 g) which transfers the fibrous material to a fiber opener (6 i) which makes the fibers 70-80 DEN fine, a compression module (7) that has a rigid gasket with saw like teeth which move the fibers to the surfaces of two perforated cylinders (7 e) which rotate counter clockwise and give a uniform thickness to the textile fabric which is then transferred for consolidation to the interlacing module (8).
 4. The machinery for the manufacturing of the composite textile material, according to claim 3, characterized by the fact that module (1) consists of a conveyor belt (1 a) which has a feeder roller (1 b) at one end that feeds a chopper (1 c) with rotating blades (1 d) for the cutting of plant fibers (FV) to a length between 5 and 100 mm, a device (1 e) for compressing the cut fibers, a horizontal conveyor belt (1 f) and an inclined conveyor belt (1 g), with nails and an equalizing roller (1 h) that rotates in the opposite direction of the conveyor belt (1 g) and which is involved in the homogenization of the plant fibers (FV) and ensures a constant material flow.
 5. The manufacturing machinery of the composite textile material in accordance with claim 3 that is characterized by the fact that if using a mixture of more types of plant fibers, one module (1) and one module (3) is used for every type of plant fiber. 